Spatio‐Temporal Variation of Soil Microplastics as Emerging Contamination After Application of Organic Mulching in Phyllostachys violascens Forests

Microplastics (MPs) are emerging contaminants of increasing concern in terrestrial ecosystems, yet their distribution patterns and ecological risks in bamboo forest soils remain underexplored. We investigated MPs contamination in experimental Phyllostachys violascens forests under different urban proximity (suburban vs. exurban) and mulch durations (none, short‐term, and long‐term). MPs abundance, morphology, and polymer composition were analyzed across three soil depths (0–10, 10–20, and 20–40 cm) and correlated with soil properties. Ecological risks were assessed using potential ecological risk index (H) and pollution load index (PLI). The results were: MPs abundance varied significantly with urban proximity and mulching duration, with the highest levels observed in exurban and short‐term mulched stands. Vertical distribution showed an initial increase followed by a decline with depth. MPs were mainly granular, gray in color, and primarily composed of polymethyl methacrylate and polyethylene terephthalate. Increased distance from urban centers and longer mulching durations led to reduced diversity in MPs morphology and polymer types, and a shift toward smaller particle sizes (50–100 μm), particularly in short‐term mulched plots. MPs particle size was negatively correlated with the proportion of soil microaggregates (p < 0.05), whereas polymer types showed significant positive correlations with soil pH, total nitrogen, hydrolyzable nitrogen, total potassium, and large aggregate proportion (p < 0.05), indicating that soil properties influence MPs distribution and composition. PLI and H indexes indicated moderate MPs contamination, corresponding to ecological risk levels III–IV in all sampling sites. Overall, mulched Ph. violascens plantations exhibit moderate MPs contamination, with elevated ecological risks in exurban areas and under short‐term mulching. These findings provide insights for targeted mitigation strategies and improved management of MPs contamination in bamboo forest ecosystems.